Conventional large cable networks comprise distributed video and data facilities to deliver content in a cable network environment. In a typical cable network, content such as videos are distributed over a backbone or core network to so-called headend resources that service one or more hubs. The hubs receive and re-distribute the content to one or more distribution nodes that each, in turn, conveys the content to a service group including multiple subscribers. The subscribers in the service group are able to tune to certain frequencies of the shared cable using a set-top box, cable modem, etc., to retrieve and play back desired content.
One conventional way to deliver video over a core network to the hubs is to produce a multi-program transport stream for transmission over a backbone of a network. The multi-program transport stream is typically a QAM (Quadrature Amplitude Modulation) data channel including multiple data streams. Subsequent to receiving the multi-program transport stream, a distribution node then initiates distribution of the data streams (e.g., variable bit rate or constant bit rate data streams) to the multiple subscribers in the service group.
One downside of continuously transmitting all available program channels over a shared cable medium to a service group is inefficient bandwidth usage. As an example, no subscribers in a service group may be tuned to play back a particular program, yet a data stream in a non-switched digital video application is continuously transmitted on the cable medium to the subscribers in the service group.
Conventional cable network applications sometimes support so-called switched digital video. In such applications, a data stream is transmitted on available bandwidth of a shared cable medium (e.g., a coaxial cable) to the members in a service group only after a particular subscriber makes a request (or tunes) to receive the data stream. Accordingly, in such switched digital video applications, if no subscriber requests to play back a data stream at a subscriber node in the service group, the data stream is not needlessly transmitted over the network to the service group in order to save on bandwidth.